The Biostatistics/Epidemiology Core will be responsible for all statistical, data management, and epidemiological aspects of the Mayo Clinic Urology O'Brien Center research grant. It is expected to serve all major projects as well as pilot projects and will be staffed by members of the Divisions of Biomedical Statistics and Informatics and Epidemiology who have expertise in statistical analysis, data management, and study design. Further, the Core investigators have extensive experience in the applications of quantitative methods to urologic and kidney problems, including nephrolithiasis. The objectives of the Core are to 1) provide high quality consultation to project investigators regarding study design, data analysis and interpretation of results, 2) maintain and extend the existing Olmsted County kidney stone database, 3) develop additional high quality linkable databases and quality control procedures for O'Brien Center research grant studies , and 4) foster and develop junior faculty in the statistical and epidemiological approach to clinical questions in nephrolithiasis.